For the 1980-1981 period of this grant we plan to perform the following work: 1. Determination of the changes in lung function induced by inhaled chlorpheniramine. A dose of inhaled chlorpheniramine with no anticholinergic activity but slight bronchodilating effect (5.5 mg) and a dose of inhaled chlorpheniramine with mild anticholinergic effect (dose-ratio 2:1 against acetylcholine) and marked bronchodilating effect will be used in separate days. Measurements of mechanisms of breathing and arterial blood gases will be recorded before and after the administration of chlorpheniramine. 2. Determination of the effect of inhaled chlorpheniramine in exercise induced asthma. Doses of 11 mg inhaled chlorpheniramine and 0.5 mg atropine (both with dose-ratios 2:1 against acetylcholine) and saline will be nebulized, in separate sessions before and after exercise induced asthma. 3. Comparative effect of inhaled chlorpheniramine (11 mg) and atropine (1.5 mg) on the resting tonus of normal, hay fever, asthmatic and bronchitic subjects. The two competitive antagonists will be used in a dose with a dose-ratio of 4:1 against their corresponding agonist. 4. protective effect of inhaled chlorpheniramine (11 mg) in ragweed induced asthma. The slopes of individual inhibition curves of specific IgE, before and after heating (30 minutes, 56 degrees C) will be plotted against individual histamine and antigen responsiveness. 5. We will also begin to determine the effect of cimetidine on the time course of histamine responses.